Tuning photovoltaic response in Bi₂FeCrO₆ films by ferroelectric poling

Abstract

Ferroelectric materials are interesting candidates for future photovoltaic applications due to their potential to overcome the fundamental limits of conventional single bandgap semiconductor-based solar cells. Although a more efficient charge separation and above bandgap photovoltages are advantageous in these materials, tailoring their photovoltaic response using ferroelectric functionalities remains puzzling. Here we address this issue by reporting a clear hysteretic character of the photovoltaic effect as a function of electric field and its dependence on the poling history. Furthermore, we obtain insight into light induced nonequilibrium charge carrier dynamics in Bi2FeCrO6 films involving not only charge generation, but also recombination processes. At the ferroelectric remanence, light is able to electrically depolarize the films with remanent and transient effects as evidenced by electrical and piezoresponse force microscopy (PFM) measurements. The hysteretic nature of the photovoltaic response and its nonlinear character at larger light intensities can be used to optimize the photovoltaic performance of future ferroelectric-based solar cells.

Non-volatile optical switch of resistance in photoferroelectric tunnel junctions

“…Moreover, it is observed that some junctions display nonreversible photoresponse (Supplementary Note 15 and Supplementary Fig. 15), as reported in ferroelectric single crystals and thin films 62,63 , and attributed to charge trapping. It thus follows that, to take full advantage of the photoresponsive ER in FTJs, the ionic transport channel should be mitigated or suppressed.…”

Thickness Dependence and Strain Effects in Ferroelectric Bi2FeCrO6 Thin Films

“…2). The c out of plane lattice parameters calculated from the two maps are of 0.3962(4) and 0.3963(4) nm while the in plane parameters are 0.3898(3) and 0.3906(2) nm. This result clearly show that the film is fully strained on the STO substrate (0.3906 nm).…”

“…13 Note also that the gap can be modulated to some extent by controlling the Fe-Cr order, 14 resulting in a conversion efficiency that is dependent on the poling history. 2 In this context, the study of the polarization reversal in BFCO and the resulting electron conduction is essential to understand the mechanisms governing the energy conversion in solar cells or other ferroelectric applications.…”

Investigation of KBiFe2O5 as a Photovoltaic Absorber

“…This proves that research on novel materials for solar cells can be quite successful and should be maintained. Standard solar cells are based on a pn-junction, however ferroelectric solar cells have emerged with a record conversion efficiency in Bi 2 FeCrO 6 of 8.1% (1,2,3).…”